Current Traccar images ship with no built-in account at all — the login
screen's Register flow creates the first user, and that user is
automatically made admin. The admin@admin.com/admin default our messages
still quoted belongs to older Traccar versions and no longer exists,
so anyone following our own output would try that login and fail.
Updated the dry-run summary, README, and final on-screen message to
describe the real flow, and to flag that self-registration stays open
to anyone who reaches the server until it's turned off (Settings →
Server → Permissions), since that's a real exposure window on a
freshly-installed instance with no way to lock it down at config time.